Means for feeding belt ammunition to heavy machine guns



MEANS FOR FEEDING BELT'AMMUNITION TO HEAVY MACHINE GUNS 'l l g" l /VTTMIVEX Aug. 29,.1944. J, D, NORTH l zsmz?" MENS' FOR FEEDING BELT AMMUNITION TO HEAVY MACHINE GUNS Filed May 12, 1'942 4 sheets-sheet i2 F/G. /.A

ATTOP/Vfy llg. 29, 1944.. J' D. NQRTH '12,357,127

MEANS FOR FEEDING BELT AMMUNITION TO HEAVY MACHINE Filed May l2, 1942 4 Sheets-Sheet 5 ATTORNEY Aug. 29, 1944.

MEANS FOR FEEDING BELT AMMUNITIAON :[O HEAVY MACHIUNE GUNS v J. D. NORTH Filed May 12, 1942 Sheets-Sheet 4 Ey I 242- J 19o 24o Q --k (-J ATTORNEY m/VENTO'Rl gMmw-fl,

Patented Aug. Z9, 1944 MEANS FOR FEEDING BELT AMMUNITION TO HEAVY MACHINE GUNS lJohn Dudley North, Wolverhampton, England, assigner to Boultonk Paul Aircraft Limited, Wolverhampton, England, a British company Application May 12, 1942, Serial No. 442,713 In Great Britain February 10, 1939 s` claims. (c1. ssi-33) This invention-relates to means for feeding belt ammunition to heavy machine guns, that is to say, machine guns which fire projectiles considerably heavier than rifle bullets.

The feeding of ammunition to guns of this type, which may fire at a Very rapid rate, particularly when mounted in aircraft, presents special problems. If the cartridges are arranged.

in magazines or chargers which are clipped on to the top of the breech, there is the difiiculty that a charger containing an adequate number of rounds is unduly heavy to be manipulated conveniently in the gun turret. It is therefore desirable to provide a belt feed for such guns. Belt feed on the other hand presents difficulties not met with when rifle ammunition is used owing to the weight and bulk of the individual rounds. Further diculties arise when it is desired to feed belt ammunition to a gun designed for magazine feed. v

In machine guns designed to be fed with ammunition from a belt, the belt feeding means and the means for stripping a round from the belt are provided in the mechanism of the gun itself. For example in o-ne design of rie calibre machine gun fed from a disintegrating link type belt, the belt is. fed to the gun by means of a camv operated lug in the top of the breech casing which engages behind the leading round of the belt and positions thisround to be withdrawn from the belt, in the direction of the axis of the round, by means of a claw provided on the leading top edge of the breech block. The link thus freed is pushed into a link ejector chute by the next round as it is fed forward.

Belt feeding and round stripping means are not provided in the mechanism of a magazine fed gun.

An object of the present invention is to provide means for feeding belt ammunition to heavy machine guns designed for magazine feed, comprising a non-disintegrating ammunition belt from which the rounds of ammunition are withdrawn from the side in a direction perpendicular to the longitudinal axis of the round, driving means for the belt and means for stripping the rounds laterally from the belt and pushing them into the breech port of the gun.

A further vobject of theinvention is to lessen any tendency for the rate of fire of the gun to be 'slowed'down by reason of the inertia of the loaded belt which is considerably greater than that of a belt containing rifle calibre ammunition.

' A further object is to ensure the accurate embodiments of the invention, hereinafter positioning of a round relative to the breech port atthe moment of its withdrawal from the belt, irrespective of the angle of elevation of the gun.

With the foregoing and other objects in View, as will hereinafter appear, the invention comprises the novel arrangement and combination of parts hereinafter described and claimed, it being understood that changes in the particuxar escribed, may be made within the scope of the claims without departing from the invention.

Particular embodiments of the invention are illustrated in the accompanying drawings in which: l

Figure 1 is a side elevation of a belt feed mechanism according to this invention,

Figure 1A is an extension of the view of Figure 1,

Figure 2 is an under-plan of Figure 1, l

Fig. 2A is an extension of the view of Figure 2,

Figure 3 is an end elevation partly in section as seen from the right in Figure 1,

Figure 4 is Aan end elevation in section of the line IV-IV in Figure 1A parts being omitted, showing a mechanism omitted from Figures 1 to 3,

Figure 5 is a view similar to Figure 1 showing a modified construction, and

Figure 6 is an end elevation in section on the.

line VI-VI in Figure 5.

Referring rst to Figures 1 to 4, the gun is indicated at Ill, its muzzle being towards the right in Figures 1 and 2 and the loading aperture or breech port I2 in the breech being at one side. The gun is carried in a cradle I4 which is mounted in trunnions, indicated at I6, Ybehind the breech port.

A feed wheel in the form of a chain drum I8 is mounted to rotate on one of the trunnions I6 in needle bearings 20. This drum is provided with teeth 22 to fit the links 24 of a jointed cartridge belt in the manner of a sprocket wheel. Each link is formed with U-shaped guides 26 (Figure 4) to receive the base of a round 28, the open side of the guides being at the side of the chain so that the rounds can be Withdrawn from the chain sideways towards the gun. The drum has a ange 30 to which is attached the outer end of a spring 32 of the clock type, the inner end of which is secured to a sleeve 34 mounted to rotate in needle bearings 36 on the hub 38 of the drum I8. The outer face of the sleeve 34 is formed with ratchet teeth 40 cooperating with similar teeth 42 on a driving sleeve 44, the teeth being held yieldingly in engagement by springs The driving sleeve 44 carries a radially prol jecting arm 52 connected to a link 54 reciprocated vertically in synchronism withthe Yopera- Y tion of the breech mechanism by mechanism to be described hereinafter, and it will be evident that the reciprocation of the link 54 will rotate the sleeve 44 alternately in opposite directions, thereby rotating the sleeve 34 stepbyA step, backward rotation being prevented by` the pawl 50.

It will be convenient first to describe the operation of the mechanismY as if the drum |8` were flxed to the sleeve 34 (in whichv case it would of course be rotated. positively step by'step in the anticlockwiseL direction) rand to explain the function of fthe spring later. Actually, such an arrangement would be within the scope of the invention in its broad aspect, although the spring confers additional advantages.

,Asmearch roundV reaches'the position X (Figures 1A and 3) opposite the breech port, I2 it is pushed sideways Yout of the link and into the breech port by a loading pawl or plunger 56 (Figureri) which consists of twohook-shaped members fixed to a spindle 58 mounted to rotate in lugs 60 carried by a slide |52 mounted in guides to move towards and away from the breech port transversely to the belt 24. This'slideis reciprocated by an arm 64 secured to a shaft 66 which is connected to the device which operates the breech mechanism of the gun (in this case a gas-operatedcylinder 68) so that the shaft is oscillated once for each shot fired, the timing being ysuch that eachround is pushed into the breech as it comes to the position X. Figure 4 shows the parts near the end ofY this movement. Before the pawl 56 begins to Ymove back the nextround comes into position,

the curved hook shape of the pawl allowing of this. The extremities Vof the pawl are lifted clear of this second round during the backward move- .ment by a resiliently-mounted tongue I0 the tip of which is encountered'by a downward'exten- Vsion 'I2 of the pawl as soon as it begins tomove backwards. When the pawl is completely retracted the extensionlZ drops into a depression I4V in the tongue. 10,. therebyenabling the pawl to fall vinto 'its vformer positiony ready to engage the next. round.V VDuring the next forward operation the extension 'I2 depresses the tongue 'I0 against theA action of the spring 16.- The pawl may be urged downwards by a spring if desired.

It will be .appreciated that;r if the drum I8 is positively driven there must necessarily be a delay, after the loading of one cartrid-ge intoV the gun,.before the. next one comes into the X position because the belt does not begin to move until thev driving sleeve 44 has made a step of movement in the. clockwise direction, ready for the next feed movement. The function of the spring 32 is tocause the drum I8, and therefore the belt24, to move immediately each round'has been pushed out ofxthe belt, without waiting for the' next operation of the ratchet mechanism;

The spring is initially stressedso that it is capable of rotating the drum anti-clockwise in relation' to-the sleeve 34 to the extenty of, say,

three rounds and @flirting theioaded belt through that distance. However, it does not have to move the drum more than one step because at the end of each step the round encounters a fixed stop 'I8 (Figure 4) in the form of an angle bracket inserted immediately above the port I2, which arrests the belt and the drum I8. As soon as this round is clear of the belt the spring immediately brings the next round into position. Immediately afterwards the spring is wound up again by the next step of movement of the sleeve 34, so` that thev same amount of energy is available for each round.

In an .alternative arrangement the spring is wound Yto an extent sufficient to feed Vseveral rounds, or even a complete belt, before being rewound. If, however, it is re-wound after each step of movement its size is a minimum and therefore the arrangement first described is preferred.

The shaft 66 is urged in the anti-clockwise or loading direction by a spring (not shown) so that'if the breech should be Vclosed when it rotates in'that direction no damage is done. It is rotated in the clockwise direction by the gas cylinder 68, which has lugs that actuate the breech mechanism through plungers 82. These Vlugs also rock a two-armed lever 84 connected by a link 86 to an arm 88 secured to the shaft 66. The spring which biases the shaft 66 may be a torsion spring'V housed Within the barrel 90 to which the lever arms 84 are attached. If the breech should be closed'When-Athe gas cylinder moves forward (to the right in Figures land 2) all that happens is that the lever 84 does not fol.- low the lug80.

Referring tQFigure 3, the link 5 4Yrwhich'wdrives the'sleeve 44 -is connected atits upper end to an arm 92carried by a sleeve 84 rotating onl a fixed pivot pinv 96. This sleeve carries anotherarm 98 connected by a link |00 to an arm |02 carried by the shaft 66. Thus the sleeve 44 is oscillated Vin synchronism with the shaft 66 and therefore with the loading pawl 56. It is to be noticed that the operative movement of the link 54 (the upward movement)` is imparted to it by the rearward movement of the gas cylinder, and not by the'spring which rocks the shaft 66 in the anticlockwise direction, l

In thel example illustrated, in Figures 1 to 4 the gun `slides in thev cradle|4, recoiling against the action of springs. The bearings for the rear end of the shaft 66 and the spindle96 are carried by a bracket |04 yfixed to the Vcradle I4. vThe bearing |06 for the front end of the shaft 66 is, however, fixed to the gun itself and therefore the hub |08 of the arm 88 is splinedas is the end of the shaft 66, to enable these two parts to slide in relation to one another without relative rotation. Y Y

Alternatively, the bearing |06 and the supports of the leverV 84 may be fixed tothe cradle, in which case the lever 84 may be actuated, not by the gas cylinder, but by the recoiling gun itself. It will be clear thatV if the cradle and the gun which it carries are-elevated above the horizontal each cartridge will be constrained to take up the same angle of elevation as the'gun itself as it comes to the loading position; Vit is always in the same position in relation to the'breech port. In some cases the axis of rotation ofthe feed wheel I8 may be displaced' downwards slightly from the axis of the trunnions to compensate for the sagging 0f the cartridges which causes their axes to be'not quite radial to thewheel.

An alternative embodiment of the invention isY illustrated diagrammatically in Figures and 6. In this embodiment the mechanism for pushing the cartridges into the breech port is the same as described above, and is not shown again. The drum I8 is replaced by a roller |80, without sprocket teeth, which is free to rotate around the axis |82 about which the gun is elevated. This roller acts as an arcuate guide for the bases of the cartridges and is made free to rotate merely to reduce friction. If desired, it could be replaced by a fixed guide in the form of a segment of a cylinder. The cartridge belt is in the form of a series of U-shaped clips 240 gripping the cartridges midway of their length and pivoted together by means of ball-and-socket joints 242 to form a chain. The limbs of the loading plunger 56 (Figures l and 4) straddle this belt or chain and are therefore able to push the cartridges out of the clips without tilting them.

The belt passes over a sprocket drum |83 the axis of which is parallel to the axis of the gun barrel and which is mounted in bearings carried by the cradle I4. It is driven intermittently by means similar t those described previously in connection with the drum I8.

In order to mantain the bases of the cartridges in contact with the roller |80 when the gun is elevated, a fixed guide plate |84 is provided which is cylindrical and concentric with the roller, and placed so that it just clears the front ends of the cartridges. This guide plate has a straight portion |86 extending downwards from it, and another straight guide -plate |88 tangential to the roller |80 is provided to guide the cartridge bases on to the roller. The bases of the cartridges slide up this straight guide |88 and then on to the roller |80. When the gun is used on aircraft, in which the gun barrel may be depressed below the horizontal, the straight guide is tangential to the roller at a point the radius of which makes an angle to the horizontal equal to the greatest angle of depression which is provided for. Lateral guide plates |90, Figure 6, are provided to restrain sideways motion of the belt and to keep it in alignment with the teeth of the sprocket drum |83. These guides enable the gun to be elevated or depressed Without interfering with the correct presentation of the cartridges to the breech port.

The guide plates |90 are in the form of circular discs fixed to the gun cradle I4, and the bearings I8| of the sprocket drum |83 are secured to one of these discs, as shown in Figure 6.

What I claim is:

l. Means for feeding belt ammunition to heavy machine guns designed for magazine feed and mounted for rotation about an axis parallel to the direction in which the rounds enter the breech port of the gun, comprising an ammunition belt from which the rounds of ammunition are withdrawn from the side in a direction perpendicular to the long axis of the round, means for feeding the ammunition belt to the breech port of the gun in a plane normal to the axis of rotation of the gun, arcuate guide means disposed about said axis of rotation for guiding the rounds to a position of correct alignment with the breech port irrespective of the angular position of the gun, a stop located on the gun adjacent the breech port for stopping each round as it reaches said port and a member carried by the gun and normally resiliently urged in a direction to push the round laterally from the belt into said port when the port opens.

2. Apparatus for feeding belt ammunition to heavy machine guns designed for magazine feed and movable in elevation about trunnions, the breech port of the gun being at the side and disposed radially of the axis of said trunnions, comprising a flexible ammunition belt supporting rounds of ammunition by their bases and from which the rounds of ammunition are withdrawn from the side in a direction perpendicular to the longitudinal axis of the round, a feed wheel over which the ammunition belt passes with the rounds of ammunition coplanar therewith, and extending radially therefrom, means for rotating said feed wheel to feed said belt towards the breech port, a stop disposed to engage each round of ammunition as it arrives opposite the' breech port of the gun, said feed wheel being mounted co-axial with the gun trunnions so that when a round is engaged by the stop opposite the breech -port it is in the correct angular position for entry into the breech, and a member carried by the gun and normally resiliently urged in a direction to push the round laterally from the belt into said port when the port opens.

3. Means for feeding belt ammunition to heavy machine guns designed for magazine feed and mounted for rotation about an axis parallel to the direction in which the rounds enter the breech port of the gun, comprising an ammunition belt from which the rounds of ammunition are withdrawn from the side in a direction perpendicular to the long axis of the round, a feed wheel for feeding the ammunition belt to the breech port of the gun in a plane normal to the axis of rotation of the gun, resilient means for rotating said feed wheel, said resilient means being initially loaded by an amount sufcient to feed a plurality of rounds of ammunition to the gun, arcuate guide means dis-posed about said axis of rotation for guiding the rounds to a position of correct alignment with the breech port irrespective of the angular position of the gun, a stop located on the gun adjacent said breech port for stopping each round as it reaches said port, a pawl normally resiliently urged in a direction to 1push the round laterally from the belt into said lport when the port opens, said pawl being shaped to permit a fresh round to be moved against the stop by said feed wheel when the rst mentioned round has been pushed into the breech port, and means responsive to the firing of the gun to restore the initial loading of said resilient means and to retract said pawl.

JOHN DUDLEY NORTH. 

